Definition of fossicks:
(v) :
(intransitive, Australia, British, New Zealand) To search for something; to rummage.
(v) :
(intransitive, Australia, British, New Zealand specifically) To search for gems, gold, etc., on the surface or in abandoned workings.
(v) :
(intransitive, Australia, British, New Zealand specifically) To elicit information; to ferret out.
(v) :
(intransitive, British, dialect) To be troublesome.